Gasoline type fuel composition



United States Patent GASOLINE TYPE;- EUELGOMPGSITIGN- Victor E. Massa, Union, N. J., .and Barrett B. Russelliird,-

Park Forest,- Illl, 3SSlgll0l'SQ't0ESSO' Research and Engineering Company; a corporati'om of'iDelaw-are No Drawing. Application October 4, 1951, Serial No. 249,818

6 Claims. (Cl.z44-69) Thisinvention concerns a novel process for minimizing formation ofcombustion deposits in an internal combustion engine. The process of. this invention may. be embodied, in novel fuel compositions operative when burned in an internal combustion engine to aid in the removal of deposits from the engines. These compositions are characterized by inclusion of aluminum alcoholate in gasoline type fuels resulting in. the deposition of aluminum compounds in the combustion chamber of an engine. These aluminum compounds are characterized by a substantially different coeflicient of expansion than those deposits ordinarily accumulating in an engine. As a result, by securing the deposition of these aluminum compounds intermixed with conventional de- .posits having substantially dilferent coefiicients of expansion, flaking of the total deposit from the engine will be achieved during variations in the temperature of the engine.

It is generally recognized in the automotive and fuel industries that a need exists for a method of minimizing or removing engine deposits from internal combustion engines. This is particularly apparent in connection with automotive engines where it is now known that engine deposits account for a substantial increase in the octane requirements of an engine after prolonged use. It has been found that due to combustion chamber deposits, it is necessary to increase the octane rating of fuel supplied to an engine by as much as to 25 octane numbers in order to prevent knocking of the engine.

By analysis of the deposits, it has been found that the engine deposits which result in an internal combustion engine burning a gasoline fuel are predominantly carbonaceous on a volume basis. A portion of the troublesome engine deposits is made up of lead salts present in the form of several diiferent types of lead compounds resulting from tetra-ethyl lead included in the fuel as an I anti-detonant. While these lead deposits are relatively heavy and make up a substantial portion of the deposit by weight, lead deposits in fact account for a small proportion of the total volume of engine deposits.

It has now been conceived that by intentionally causing deposition of a material having a substantially different coefiicient of expansion, the admixture of this material with carbonaceous and lead deposits in the engine will cause fracture of the deposits so as to maintain the engine in a relatively clean condition. In accordance with this invention therefore, a metal compound is to be injected into an internal combustion engine so as to secure deposition in the engine of a metal salt or oxide preferably having a high coefiicient of expansion, since carbonaceous deposits have a relatively low coeflicient of expansion. Intermingling of the deposits of this metal compound with the conventional carbonaceous deposits creates a condition causing the deposits to flake away from the engine during variations in engine temperature. A portion of this effect may be secured during each cycle of engine operation, although there is greater oppor- 2: tunity for scaling ofthischaracter to occur duringidle periods at which-the engine temperature can drop'toambient temperatures. In-any'case, the flaked deposits are carried from the engine with the exhaust products'd'uring successive engine operation.

In orderto secure-this objective, itis necessary to supply a' suitable metal compound to the engine to'permit deposit in theengineof a substancehaving a high coefii'ci'ent' of expansion; To attain this objective it isundesirable to employ stable metal compounds, which; for the most part would simply pass through the-engine Without deposition in-the combustion chamber. However, if compounds such as aluminum alcoholates are employed; these compounds will be readily decomposed under the conditions existing ifthe combustion zone so astodeposit in the engine in the form principally ofaluminum oxide. Thus, moisture resulting from the combustion of the fuelwill readily hydrolyze the aluminumalcohol ateresulting in the deposition of alumina in the combustion chamber.

Aluminum alcoholates having from 3 to 10 carbon atoms may be employed in the practice ofthis'invention. An example" of' such alcoholates is aluminum; isdptopoxide which is presently contemplated as being a-preferred compound. Due to the relatively low volatility of aluminum alcoholates it is preferred that the lower molecular Weight aluminum alcoholates be employed so that the C3 to C5 aluminum alcoholates are generally preferable. These compounds are to be employed in a range of about 0.001% to about 0.1% by weight in the fuel compositions of this invention. Employing concentrations of the aluminum compound outside of this range is generally not desired. For continuous operation in an engine, it-

is generally suitable to employ no more than about 0.01% by Weight of the aluminum compounds.

Solution of the selected aluminum alcoholate in a fuel composition may be aided by a suitable agent to keep the aluminum compound in suspension or to solutize the aluminum alcoholate. Peptizing agents are generally operative to provide this function. Examples of such compounds are sodium petroleum sulfonate and an alkali metal or alkaline earth metal alkyl phenol sulfide or disulfide such as barium diisobutyl phenol sulfide, employed alone or in combination. Inclusion of about 0.001% to about 0.01% of these compounds by weight is generally satisfactory to solubilize the aluminum alcoholates.

It is particularly preferred in obtaining the benefits of this invention to include the aluminum alcoholate alone or together with a solutizer, as identified, in an auxiliary fluid to be injected in the engine. Thus, in cases in which an engine has been provided with an auxiliary fuel tank and injector system, it is valuable to practice the present invention by injecting the aluminum alcoholate through this system. In this case it is particularly desirable to dissolve the aluminum alcoholate in an alcohol which may then be injected into the engine according to the conventional practice.

In the case in which the aluminum alcoholate is included as a constituent in conventional gasoline type fuels any desired type of fuel base may be employed. Thus the fuel base may be defined as a mixture of hydrocarbons boiling in the gasoline boiling range derived from refining of petroleum oil or from suitable hydrocarbon synthesis processes. The gasoline base may be a virgin, catalytically cracked, thermally cracked or hydroformed gasoline, or any of the other conventional gasoline bases. In addition to the aluminum alcoholate and a solutizer for the aluminum alcoholate, if desired, conventional gasoline additives may be employed. Thus, a lead alkyl antidetonant, lead scavenging agents, dyes, anti-oxidants, solvent oils, etc. may also be included in the compositions.

i As indicated therefore, the present invention concerns a method for minimizing adherence of engine deposit formations. According to this method, engine deposits may be substantially reduced by injection of a minor portion of aluminum alcoholate, having from 3, to 10 carbon atoms into the engine. The aluminum alcoholate may be introduced in a separate injection system or may be introduced in admixture with any desired type of gasoline. In either case the aluminum alcoholate decomposes in the combustion zone to form aluminum oxide which deposits on those portions of the engine on which carbonaceous and lead deposits ordinarily form. The aluminum oxide, having a substantially different coefiicient of expansion from the other constituents of the engine deposit admixed therewith, creates a flaking effect particularly when the engine has had an opportunity to cool off during shut-down after periods of engine operation. Thereafter on subsequent operation of the engine these deposits are for the most part blown from the engine through the exhaust system. It is apparent that fuels containing alcoholates may be used continuously in an engine to minimize deposits in this manner, or alternatively intermittent operation utilizing the fuel compositions of this invention may be carried out.

What is claimed is:

1. An improved gasoline composition containing a lead alkyl anti-detonant and 0.001 to 0.1% of an aluminum alcoholate having from 3 to 10 carbon atoms.

2. The composition of claim 1 having from 3 to 5 carbon atoms.

3. The composition defined by claim 1 in which the said aluminum alcoholate constitutes aluminum isopropoxide.

4. The composition defined by claim 1 including about 0.001% to 0.01% of a peptizing agent adapted to solubilize the said aluminum alcoholate.

5. The composition defined by claim 4 in which the said peptizing agent constitutes sodium petroleum sulfonate.

6. The composition defined by claim 4 in which the said peptizing agent constitutes an alkali metal alkyl phenol sulfide.

References Cited in the file of this patent UNITED STATES PATENTS 1,849,456 John Mar. 15, 1932 2,086,775 Lyons et a1 July 13, 1937 2,429,707 Catalano Oct. 28, 1947 2,460,700 Lyons Feb. 1, 1949 2,553,183 Caron et al. May 15, 1951 2,560,542 Bartleson et al July 17, 1951 FOREIGN PATENTS 496,692 Great Britain 1938 965,315 France Sept. 8, 1950 

1. AN IMPROVED GASOLINE COMPOSITION CONTAINING A LEAD ALKYL ANTI-DETONANT AND 0.001 TO 0.1% OF AN ALUMINUM ALCOHOLATE HAVING FROM 3 TO 10 CARBON ATOMS. 